Catalytic hydrogenation of unsaturated aldehydes and ketones



A. F. MacLEAN ET AL 2,825,743 CATALYTIC HYDROGENATION 0F UNSATURATED March 4, 1958 ALDEHYDES AND KETONES Filed Aug. 30, 1955 Conua/vas? a 5 6 \.\T\\ me w mm M www m wm U Mw 7,

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Geom/141.0151005 CATALYTIC HYDROGENATION or -UNsrUL Y RATED ALDEHYDES AND KEToNEs Alexander F. MacLean and VCharles C. Hobbs, Jr., Corpus Christi, Tex., assgnors vto Celanese Corporation of America, NewYork, N. Y., a corporation of Delaware Application August 30, 1955,- Serial No. 551,426YYY 14 Claims. 4(Cl. -260-593) This application is a continuation-impart lof our copending application Serial No'. 459,798,iled October i,-

1954, now abandoned.

This invention relates to reactions of ethylenically unsaturated carbonyl compounds and relates more particularly to the catalytic hydrogenation of'such compounds.

lt is an object of this invention toprovide a novel'processand apparatus for use in the catalytic hydrogenation of ethylenically unsaturated carbonyl compounds such as crotonaldehyde.

Another object of this invention is the provision of a new 'process and apparatus for carrying out the continuous catalytic hydrogenation of ethylenically unsaturated carbonylcompounds using a fixed bed of catalyst under such' conditions that the catalyst has a 'long lifeV and the ethylenically unsaturated carbonyl compound is converted in' very high yields to saturated compounds such as saturated alcohols` and saturated aldehydes;

In accordance with this invention the ethylenically unsaturated carbonyl compound and hydrogen are passed continuously through a ixed bed of a hydrogenation catalyst maintained at an elevated temperature. A portion ofV the whole of the reacted mixture emerging from'the bed of catalyst is drawn oif and -the products of the reaction recovered therefrom, while the balance of the reacted mixture is recycled by mixing it with the fresh feed of the ethylenically unsaturated carbonyl compound and hydrogen." Advantageously, the portion which is recycled is larger than the portion which is drawn off.

The process of this invention has been found to be especially useful for the hydrogenation of na-ethylenicallyy unsaturated carbonyl compounds. These include aliphatic Valdehydes such as crotonaldehyde, acrolein,

methacrolein, and Z-ethylhex-Z-enal, aromatic aldehydes such as cinnamaldehyde, and ketones such as mesityl oxide and methyl vinyl ketone and methyl isopropenyl ketone.

A very satisfactory catalyst for use in the"process of this invention is a copper catalyst, particularly 'a copper catalyst which contains oxides of elements suchV as chro-` mium, barium, and zinc, which oxides act as promoters and stabilizers, as is well known in the art. Such a catalyst can be prepared by the reduction, as by means of hydrogen, of pellets of copper oxide or hydroxide mixed with said other oxides, or the corresponding hydroxides. It may also be prepared by reducing, with hydrogen, a coating comprising a mixture of said copper oxide or hydroxide and said other oxides or hydroxides, which mixture has been previously deposited on an inactive carrier, such as porous inert alumina or kieselguhr. Examples of other copper catalysts which have been employed successfully in the practice of this invention include the product obtained by reducing, with hydrogen, a mixture of cupric oxide and sodium silicate, said mixturecontaining, for example, to 20% of sodium silicate.

In the practice of the Yprocess of thisinvention, thepro-` portions ofthe reactants and the proportion ofthe reacted ate-ut mixturetwhich is recycled may be varied.- Advantageously'i the `molar'ratioof hydrogen to' ethylenically unsaturatedcarbonyl compound inthe fresh feed ranges'from about 1:1 tol 80:1, while -the proportion of th'e'wholelreacted mixture which is recycled is about 50 to 95% -by weight of the' total-mixture emerging from the bed of cataly'stf' In the preferred embodiment of this invention,in which' a copper catalystis employed, the temperature `of the reaction mixture and catalyst is maintained belowabout` 300 C., preferably below 260 C., but above 220"Cf Thel recycling of a portion of lthe reaction products "enf ables this temperature to be controlled uniformly and easily by regulation-of the recycle rate.

The recycling of a portion of the whole of the reacted mixture may be carried out in anydesired manner. Thus, the portion of the hot reacted mixture to be-recycled may be drawn ofl'from the reactor containing the bed of` catalyst Vand blended with one orboth of the fresh reactants, i. e. the hydrogen and the ethylenically unsaturated car:y bonyl compound, by means of a suitable pump. Advantageouslythis pumpk is in the form of a jet oraspirating device Vin which one or both of the reactants is passed atv high speed through a Venturi tube and thereV are mea-ns connecting said Venturi tube to theoutlet of the reactor` so that a portion of the reacted mixture is sucked through the Venturi tube and intimately blended-1 withv the react-ant yor reactants. If desired, a stream of liquid ethylenically unsaturated carbonyl compounds mayber sprayed into and volatilized in a stream of the hot reacted'mixture being. recycled, before or after theflatter is mixed Withfthe hydrogen.

Often two major products, a'vsaturatedY aldehyde and,

a saturated alcohol, are produced by hydrogenation of theA ethylenically unsaturated carbonyl compound in accordance with this invention. Thus, on hydrogenation of crotonaldehyde there are 'obtained both butanol and butyraldehyde. in order to increase the yield of onexof the desired products it is advantageous lto separate Vthe other product therefrom and to recycle said other prcrcl-k uct, as by mixing it with the ethylenicallyunsaturated*care bonylvcompound being fed to the reactor.: Thus, inthe case of the hydrogenation of crotonaldehyde, the yieldi of butyraldehyde may be increased considerably by' separat-y ing, as by a distillation procedure, the butanol from ,theA condensed products of reaction and mixing the separated butanol with the fresh crotonaldehyde feed, preferably-by mixing vapors of the butanol with vaporized crotonalde-.l hyde. Conversely, the yield of butanol may be raisedlapi preciably by separating the butyraldehydelfrom the coil-V densed reaction products and returning this butyraldehyde' to the reactor.

One embodiment of this invention vis illustratedlfdii' agrammatically in the accompanying drawing-Which' is a side view, with parts in cross-section, of an apparatus useful for the hydrogenation of ethylenically unsaturated carbonyl compounds.

Referring now to the drawing, referenceVV numeralllt designates a reactor which contains a bed 12 of solid' nely divided catalyst supported on a screen orother foraminous element 13. Situated belowV the reactor 11 is a preheater 14, which is provided with a heating'V jacket 16, of any suitable type. f

Vaporized crotonaldehyde, `or other ethylenical'lyun; saturated carbonyl compound, is fed into the preheater' 14 through an adju-stable valve 17 and inlet 18, while a mixture `of hydrogen and recycled reactedl mixtureis fed into the Vpreheater through an inlet 19. The resulting mixture of crotonaldehyde, hydrogen and recycyledreacted mixture passes frorn the preheater 14 through'the" bed i2 where the hydrogenation of the crotonaldehyde takes place. A portion ofthe hot reactedmixture-passcs Patented Mar. 4, 1958 distillation.

Vthrough an outlet 21to a condenser 22 andthe resulting condensed liquid is collected in a cooled receiver 23 provided with a vent24 for the uncondensed gases. Another portion; of the hot reactedniixture; passes :through alroutlet 26 `throughau adjustable valve27 to. an aspiratoror jetfpumpqZS havinga venturils'ectioni29. `vIjlydrogen` under pressurey is supplied Yto Ythe `interior ofj the jet pump V28 through an` adjustable valveg31 and arnozzle 32,'` thepassageof the hydrogen-at high Vspeedthrough the venturisectionv 29serving to suck, the hot reacted mixture into thejet pump V28.,YA The Vresulting blend of hytrQgen-andgrtedmixture Passes Ihreueha heating z qne a3 ana a pipe ,3ft to :11e 1111er 19, rv1f desatar-the reactorrllA may.A be v provided with suitable heating or @Olingmesf I L w.;

The'V following examples are' given vto* `illustrate this -in- @aan fathers. Y Y

Y i;*Crotonaldeliydecontaining 6.5 weight of water l genatedcontinuously in an apparatus of the type shown 190 to210" C. and then passed upward through' a hot 'Y catalyst bed of uniform diameter. The catalyst bed comprises trablets-of porous inertV alumina Vs x 1/8 in Size coated Vwith a mixture'of 4.8%, based on the weight of the coated particles, of freshly reduced copper, and Y0.45%, based on the weight offthe Vcoated particles, of ohromic Oxide. The space velocity (in terms of volumes Yof* reactants, at standard conditionsV per bulk volume of catalyst per hour) is 575 hour-1. During the reaction the temperature in the catalyst bed is measured atV various points along the path Vofthe reactants through the catalyst. After 1 hour of Voperation the maximum tempera- Vture in the catalyst bed is about 250 C. and this telnperature is attained at a point about Mt the height of the catalyst bed measured from the bot-tom of said bed. The

temperatures below yand above this point are lower than 250! CI, indicating that reaction is essentiallyYY complete at this point,tthe fallin temperature above this point being due to losses of heat to the atmosphere, as by radiaion. After VLl-hours of Voperation the maximum temperature isV still about 250 C. and occurs at the same point, while after 90 hours of operation the maximum temperature is about 235 C. and occurs at the same point. The portion of the reacted mixtureV Which is not recycled is Withdrawn continuously, condensed at a temperature of 8 C., and separated into butanol and butyraldehyde by Throughout the run, the extent of conversion ofV the crotonaldehyde to butyraldehyde and butanol remains constant at 99%.

Example II perature during the continuous operation show a maximum temperature of-340 C.V at rst, falling to 320 C. after41 hours, and show that the point of maximum temperature moves upward through the catalyst bed, indicating progressive deactivation of the lower portions of 'the bed. During 41 hours of operation the'extent of conversion of crotonaldehyde to butyraldehyde and butanol Y Example III "'Mesityl oxideV containing 2.1% of water is hydro- Y ture is heated-to a temperature of 160 to-tl90 C. and thenY remains at 99% .but after 481/2 hours it drops to 64.3%.

tained from the receiver is distilled to separate the methyl isobutyl ketone from the methyl isobutyl carbinol. All of the latter is returned to the reactor by mixing it with the mesityl oxide feed. `Throughout the reaction three moles of hydrogen vare fed for each mole of mesityl oxide.V TheV volumetric-ratio `of recycled hot reacted mixture toV hydrogen is4 maintained at about 5:1 so that %'fof the whole reacted mixture emerging from the bed Yof catalyst is recycled Awithout separation.V The blend of reactants andV reacted :mixtur-etis heated Yto atemperature of to C., and then passedupward throughthe hot catalyst bed which is identical with that of Example I. The space velocity V(in termsof volumes of hydrogen and fresh mesityl oxide at standard conditions per bulk volume of catalyst per hour) is'585 hour-1. mum Vtemperature attained in the .reactor is 300 C. The

'yield of methyl'isobutylketone is substantially quantita-Y tive.

Example V Crotonaldehyde containing 6.5% of wateris hydrogenated continuously in an apparatus of the typeshown,

in the drawing.YV The condensed reaction product obtained from` the receiver isy distilled to separate theA butyraldehyde fromthe butanol. All of the butyraldehyde is returned to the reactor by mixing it with the,

crotonaldehyde feed.V Throughout the reaction 10 moles ofhydrogen are fed for each mole of crotonaldehyde. The volumetric ratio of recycled hot reacted mixture to hydrogen is maintained in'the neighborhood of 325:1.

The blend of reactants and reacted mixture is heated to a temperature Yof 160 to 190 C: and then passed upward hour-1. vThe maximum temperature attained in the reactor is 250 C.V TheY yield ofbutanol and the efliciency of conversion torbutanol Yare substantially quantltatrve.

- Example/,V

Crotonaldehyde containing 6.5% ofV water isthydrogenated continuously in an apparatus of the type shown in the drawing.Y The condensed reaction product obtained from the receiver is distilled toseparate the butyraldehyde from the butanol. All of the butanol is returned to the reactor by mixingit with the Vcrotonaldehyde feed. Throughout the reactionV 1.6 moles of hydrogen are fed for each mole of crotonaldehyde. The volumetric ratio of recycled hot reacted mixtureto hydrogen is maintained at about 6.3:1. The blend of reactants and reacted mixpassed upward through the hot catalyst bed which is identical with that of Example I. The spacevelocity (in terms of volumes of VKhydrogen and Yfresh `crotonaldehyde at standard conditions per bulk volume of catalyst per hour) is 360 hour-1., When the volume of separated recycled butanol is considered,l tne space velocity (in terms of Volumes ofhydrogem'fresh crotonaldehyde and separated recycled butanol at standard conditions) is in the neighborhood of 420 hour-1. The maximum temperature attained in the reactor` isr265Vv C.A The yield of butyraldehyde and the eiciency ofv conversiony to butyraldehyde are substantially quantitative. `It isV to be ,understood that the foregoing detailed description ismerely given by wayl of illustration and that many variations maybe made therein without departing from the spirit of our invention.

Having described 'our invention, what `We desire to secureby Letters Patent is:V

' l.A Process for the hydrogenation of unsaturated compounds. which comprises continuously passing a feed of hydrogen and an ethylenically unsaturated carbonyl compound selected fronrthe group consistingof aldehydea The maxiand ketones into contact with a bed of catalyst for the hydrogenation of said compound in a reaction zone and recycling a part of the whole reacted mixture leaving the bed to the reaction zone by mixing said part with said feed, said part and vsaid whole being of the same composition.

2. Process for the hydrogenation of unsaturated compounds which comprises continuously passing a gaseous feed of hydrogen and an @,-ethylenically unsaturated carbonyl compound chosen from the group consisting of aldehydes and ketones into Contact with a bed of catalyst for the hydrogenation of said compound in a reaction zone and recycling a part of the whole reacted mixture leaving the bed tothe reaction zone by mixing said part with said feed, said part and said whole being of the same composition.

3. Process for the hydrogenation of unsaturated cornpounds which comprises continuously passing a feed of hydrogen and an ethylenically unsaturated carbonyl compound chosen from the group consisting of aldehydes and ketones into contact with a bed of catalyst for the hydrogenation of said compound in a reaction zone and recycling a part of the whole reacted mixture leaving the bed to the reaction Zone by mixing said part with said feed while withdrawing the remainder of said reacted mixture from the reaction zone, said part and said whole being of the same composition, said remainder comprising as products a saturated alcohol and a saturated carbonyl compound, recovering one of said products from said remainder and recycling the other of said products by mixing it with said feed.

4. Process for the hydrogenation ef unsaturated compounds which comprises continuously passing a feed of hydrogen and an e,ethylenically unsaturated carbonyl compound chosen from the group consisting of aldehydes and ketones into contact with a bed of catalyst for the hydrogenation of said compound in a reaction zone and recycling a part of the whole reacted mixture leaving the bed to the reaction zone by mixing said part with said feed while withdrawing the remainder of said reacted mixture from the reaction zone, said part and said whole being of the same composition, said remainder comprising as products a saturated alcohol and a saturated carbonyl compound, recovering said alcohol from said remainder, and recycling said saturated carbonyl compound by mixing it with said feed.

5. Process for the hydrogenation of unsaturated compounds which comprises continuously passing a feed of hydrogen and an a, -ethylenically unsaturated carbonyl compound chosen from the group consisting of aldehydes and ketones into contact with a bed of catalyst for the hydrogenation of said compound in a reaction zone and recycling a part of the whole reacted mixture leaving the bed to the reaction zone by mixing said part with said feed while withdrawing the remainder of said reacted mixture from the reaction zone, said part and said Whole being of the same composition, said remainder comprising as products a saturated alcohol and a saturated carbonyl compound, recovering said saturated carbonyl compound from said remainder, and recycling said alcohol by mixing it with said feed.

6. Process as set forth in claim 1 in which about 50 to 95% of the whole reacted mixture leaving the reaction zone is recycled.

7. Process as set forth in claim 2 in which the unsaturated carbonyl compound is crotonaldehyde.

8. Process as set forth in claim 2 in which the unsaturated carbonyl compound is mesityl oxide.

9. Process for the hydrogenation of crotonaldehyde which comprises continuously passing a gaseous feed of hydrogen and crotonaldehyde into contact with a fixed bed of a catalyst for the hydrogenation of the crotonaldehyde in a reaction zone and recycling a major part of the whole gaseous reacted mixture leaving the reaction zone by mixing said part with said feed while withdrawing the remainder of said reacted mixture from the reaction zone and recovering butanol and butyraldehyde from said remainder, said part and said whole being of the same composition.

10. Process asset forth in claim 9 in which said catalyst is a copper base catalyst.

11. Process as set forth in claim 10 in which the temperature in the catalyst bed is not above 300 C.

12. Process for the hydrogenation of crotonaldehyde which comprises passing a gaseous feed of hydrogen and crotonaldehyde through a bed of a solid copper base catalyst for the hydrogenation of the crotonaldehyde in a reaction zone at a temperature of about 220 to 300 C. and recycling part of the Whole hot gaseous reacted mixture leaving the reaction zone by mixing 50 to 95% of said whole hot gaseous reacted mixture with said feed while withdrawing the remainder of said reacted mixture from the reaction zone and recovering butanol and butyraldehyde from said remainder.

13. Process for the hydrogenation of crotonaldehyde which comprises continuously passing a gaseous feed of hydrogen and crotonaldehyde into contact with a fixed bed of a catalyst for the hydrogenation of the crotonaldehyde in a reaction zone and recycling a major part of the whole gaseous reacted mixture leaving said bed to the reaction zone by mixing said part with said feed while withdrawing the remainder of said reacted mixture from the reaction zone, said part of and said Whole hot gaseous reacted mixture having the same composition, said remainder comprising butanol and butyraldehyde, recovering butyraldehyde and butanol from said remainder and recycling the butyraldehyde by mixing it with said feed.

14. Process for the hydrogenation of crotonaldehyde which comprises continuously passing a gaseous feed of at least three parts of hydrogen with each one part of crotonaldehyde into contact with a fixed bed of a catalyst for the hydrogenation of the crotonaldehyde in a reaction zone and recycling a major part of the whole gaseous reacted mixture leaving the reaction zone by mixing said part with said feed While withdrawing the remainder of said reacted mixture from the reaction zone, said part of and said whole gaseous mixture having the same composition, said remainder comprising butanol and butyraldehyde, recovering butyraldehyde and butanol from said remainder and recycling the butanol by mixing it with said feed.

References Cited in the le of this patent UNITED STATES PATENTS 2,367,078 Weizmann Jan. 9, 1945 2,501,708 Bewley et al Mar. 28, 1950 2,658,921 Alheritiere Nov. 10, 1953 

1. PROCESS FOR THE HYDROGENATION OF UNSATURATED COMPOUNDS WHICH COMPRISES CONTINUOUSLY PASSING A FEED OF HYDROGEN AND AN ETHYLENICALLY UNSATURATED CARBONYL COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALDEHYDES AND KETONES INTO CONTACT WITH A BED OF CATALYST FOR THE HYDROGENATION OF SAID COMPOUND IN A REACTION ZONE AND RECYCLING A PART OF THE WHOLE REACTED MIXTURE LEAVING THE BED TO THE REACTION ZONE BY MIXING SAID PART WITH SAID FEED, SAID PART AND SAID WHOLE BEING OF THE SAME COMPOSITION. 